1 files changed, 384 insertions, 220 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 639fce4d2ca..21756814d99 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -94,8 +94,7 @@ struct pcpu_chunk {
 	int			map_alloc;	/* # of map entries allocated */
 	int			*map;		/* allocation map */
 	bool			immutable;	/* no [de]population allowed */
-	struct page		**page;		/* points to page array */
-	struct page		*page_ar[];	/* #cpus * UNIT_PAGES */
+	unsigned long		populated[];	/* populated bitmap */
 };
 
 static int pcpu_unit_pages __read_mostly;
@@ -129,9 +128,9 @@ static int pcpu_reserved_chunk_limit;
  * Synchronization rules.
  *
  * There are two locks - pcpu_alloc_mutex and pcpu_lock.  The former
- * protects allocation/reclaim paths, chunks and chunk->page arrays.
- * The latter is a spinlock and protects the index data structures -
- * chunk slots, chunks and area maps in chunks.
+ * protects allocation/reclaim paths, chunks, populated bitmap and
+ * vmalloc mapping.  The latter is a spinlock and protects the index
+ * data structures - chunk slots, chunks and area maps in chunks.
  *
  * During allocation, pcpu_alloc_mutex is kept locked all the time and
  * pcpu_lock is grabbed and released as necessary.  All actual memory
@@ -188,16 +187,13 @@ static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
 		(pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
 }
 
-static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
-				      unsigned int cpu, int page_idx)
+static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
+				    unsigned int cpu, int page_idx)
 {
-	return &chunk->page[pcpu_page_idx(cpu, page_idx)];
-}
+	/* must not be used on pre-mapped chunk */
+	WARN_ON(chunk->immutable);
 
-static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
-				     int page_idx)
-{
-	return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
+	return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 }
 
 /* set the pointer to a chunk in a page struct */
@@ -212,6 +208,34 @@ static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
 	return (struct pcpu_chunk *)page->index;
 }
 
+static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
+{
+	*rs = find_next_zero_bit(chunk->populated, end, *rs);
+	*re = find_next_bit(chunk->populated, end, *rs + 1);
+}
+
+static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
+{
+	*rs = find_next_bit(chunk->populated, end, *rs);
+	*re = find_next_zero_bit(chunk->populated, end, *rs + 1);
+}
+
+/*
+ * (Un)populated page region iterators.  Iterate over (un)populated
+ * page regions betwen @start and @end in @chunk.  @rs and @re should
+ * be integer variables and will be set to start and end page index of
+ * the current region.
+ */
+#define pcpu_for_each_unpop_region(chunk, rs, re, start, end)		    \
+	for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
+	     (rs) < (re);						    \
+	     (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
+
+#define pcpu_for_each_pop_region(chunk, rs, re, start, end)		    \
+	for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end));   \
+	     (rs) < (re);						    \
+	     (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
+
 /**
  * pcpu_mem_alloc - allocate memory
  * @size: bytes to allocate
@@ -545,42 +569,197 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
 }
 
 /**
- * pcpu_unmap - unmap pages out of a pcpu_chunk
+ * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
+ * @chunk: chunk of interest
+ * @bitmapp: output parameter for bitmap
+ * @may_alloc: may allocate the array
+ *
+ * Returns pointer to array of pointers to struct page and bitmap,
+ * both of which can be indexed with pcpu_page_idx().  The returned
+ * array is cleared to zero and *@bitmapp is copied from
+ * @chunk->populated.  Note that there is only one array and bitmap
+ * and access exclusion is the caller's responsibility.
+ *
+ * CONTEXT:
+ * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
+ * Otherwise, don't care.
+ *
+ * RETURNS:
+ * Pointer to temp pages array on success, NULL on failure.
+ */
+static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
+					       unsigned long **bitmapp,
+					       bool may_alloc)
+{
+	static struct page **pages;
+	static unsigned long *bitmap;
+	size_t pages_size = num_possible_cpus() * pcpu_unit_pages *
+			    sizeof(pages[0]);
+	size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
+			     sizeof(unsigned long);
+
+	if (!pages || !bitmap) {
+		if (may_alloc && !pages)
+			pages = pcpu_mem_alloc(pages_size);
+		if (may_alloc && !bitmap)
+			bitmap = pcpu_mem_alloc(bitmap_size);
+		if (!pages || !bitmap)
+			return NULL;
+	}
+
+	memset(pages, 0, pages_size);
+	bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
+
+	*bitmapp = bitmap;
+	return pages;
+}
+
+/**
+ * pcpu_free_pages - free pages which were allocated for @chunk
+ * @chunk: chunk pages were allocated for
+ * @pages: array of pages to be freed, indexed by pcpu_page_idx()
+ * @populated: populated bitmap
+ * @page_start: page index of the first page to be freed
+ * @page_end: page index of the last page to be freed + 1
+ *
+ * Free pages [@page_start and @page_end) in @pages for all units.
+ * The pages were allocated for @chunk.
+ */
+static void pcpu_free_pages(struct pcpu_chunk *chunk,
+			    struct page **pages, unsigned long *populated,
+			    int page_start, int page_end)
+{
+	unsigned int cpu;
+	int i;
+
+	for_each_possible_cpu(cpu) {
+		for (i = page_start; i < page_end; i++) {
+			struct page *page = pages[pcpu_page_idx(cpu, i)];
+
+			if (page)
+				__free_page(page);
+		}
+	}
+}
+
+/**
+ * pcpu_alloc_pages - allocates pages for @chunk
+ * @chunk: target chunk
+ * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
+ * @populated: populated bitmap
+ * @page_start: page index of the first page to be allocated
+ * @page_end: page index of the last page to be allocated + 1
+ *
+ * Allocate pages [@page_start,@page_end) into @pages for all units.
+ * The allocation is for @chunk.  Percpu core doesn't care about the
+ * content of @pages and will pass it verbatim to pcpu_map_pages().
+ */
+static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
+			    struct page **pages, unsigned long *populated,
+			    int page_start, int page_end)
+{
+	const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
+	unsigned int cpu;
+	int i;
+
+	for_each_possible_cpu(cpu) {
+		for (i = page_start; i < page_end; i++) {
+			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
+
+			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
+			if (!*pagep) {
+				pcpu_free_pages(chunk, pages, populated,
+						page_start, page_end);
+				return -ENOMEM;
+			}
+		}
+	}
+	return 0;
+}
+
+/**
+ * pcpu_pre_unmap_flush - flush cache prior to unmapping
+ * @chunk: chunk the regions to be flushed belongs to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages in [@page_start,@page_end) of @chunk are about to be
+ * unmapped.  Flush cache.  As each flushing trial can be very
+ * expensive, issue flush on the whole region at once rather than
+ * doing it for each cpu.  This could be an overkill but is more
+ * scalable.
+ */
+static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
+				 int page_start, int page_end)
+{
+	unsigned int last = num_possible_cpus() - 1;
+
+	flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
+			   pcpu_chunk_addr(chunk, last, page_end));
+}
+
+static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
+{
+	unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
+}
+
+/**
+ * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
  * @chunk: chunk of interest
+ * @pages: pages array which can be used to pass information to free
+ * @populated: populated bitmap
  * @page_start: page index of the first page to unmap
  * @page_end: page index of the last page to unmap + 1
- * @flush_tlb: whether to flush tlb or not
  *
  * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
- * If @flush is true, vcache is flushed before unmapping and tlb
- * after.
+ * Corresponding elements in @pages were cleared by the caller and can
+ * be used to carry information to pcpu_free_pages() which will be
+ * called after all unmaps are finished.  The caller should call
+ * proper pre/post flush functions.
  */
-static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
-		       bool flush_tlb)
+static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
+			     struct page **pages, unsigned long *populated,
+			     int page_start, int page_end)
 {
-	unsigned int last = num_possible_cpus() - 1;
 	unsigned int cpu;
+	int i;
 
-	/* unmap must not be done on immutable chunk */
-	WARN_ON(chunk->immutable);
+	for_each_possible_cpu(cpu) {
+		for (i = page_start; i < page_end; i++) {
+			struct page *page;
 
-	/*
-	 * Each flushing trial can be very expensive, issue flush on
-	 * the whole region at once rather than doing it for each cpu.
-	 * This could be an overkill but is more scalable.
-	 */
-	flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
-			   pcpu_chunk_addr(chunk, last, page_end));
+			page = pcpu_chunk_page(chunk, cpu, i);
+			WARN_ON(!page);
+			pages[pcpu_page_idx(cpu, i)] = page;
+		}
+		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
+				   page_end - page_start);
+	}
 
-	for_each_possible_cpu(cpu)
-		unmap_kernel_range_noflush(
-				pcpu_chunk_addr(chunk, cpu, page_start),
-				(page_end - page_start) << PAGE_SHIFT);
-
-	/* ditto as flush_cache_vunmap() */
-	if (flush_tlb)
-		flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
-				       pcpu_chunk_addr(chunk, last, page_end));
+	for (i = page_start; i < page_end; i++)
+		__clear_bit(i, populated);
+}
+
+/**
+ * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
+ * TLB for the regions.  This can be skipped if the area is to be
+ * returned to vmalloc as vmalloc will handle TLB flushing lazily.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
+				      int page_start, int page_end)
+{
+	unsigned int last = num_possible_cpus() - 1;
+
+	flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
+			       pcpu_chunk_addr(chunk, last, page_end));
 }
 
 static int __pcpu_map_pages(unsigned long addr, struct page **pages,
@@ -591,35 +770,76 @@ static int __pcpu_map_pages(unsigned long addr, struct page **pages,
 }
 
 /**
- * pcpu_map - map pages into a pcpu_chunk
+ * pcpu_map_pages - map pages into a pcpu_chunk
  * @chunk: chunk of interest
+ * @pages: pages array containing pages to be mapped
+ * @populated: populated bitmap
  * @page_start: page index of the first page to map
  * @page_end: page index of the last page to map + 1
  *
- * For each cpu, map pages [@page_start,@page_end) into @chunk.
- * vcache is flushed afterwards.
+ * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
+ * caller is responsible for calling pcpu_post_map_flush() after all
+ * mappings are complete.
+ *
+ * This function is responsible for setting corresponding bits in
+ * @chunk->populated bitmap and whatever is necessary for reverse
+ * lookup (addr -> chunk).
  */
-static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
+static int pcpu_map_pages(struct pcpu_chunk *chunk,
+			  struct page **pages, unsigned long *populated,
+			  int page_start, int page_end)
 {
-	unsigned int last = num_possible_cpus() - 1;
-	unsigned int cpu;
-	int err;
-
-	/* map must not be done on immutable chunk */
-	WARN_ON(chunk->immutable);
+	unsigned int cpu, tcpu;
+	int i, err;
 
 	for_each_possible_cpu(cpu) {
 		err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
-				       pcpu_chunk_pagep(chunk, cpu, page_start),
+				       &pages[pcpu_page_idx(cpu, page_start)],
 				       page_end - page_start);
 		if (err < 0)
-			return err;
+			goto err;
 	}
 
+	/* mapping successful, link chunk and mark populated */
+	for (i = page_start; i < page_end; i++) {
+		for_each_possible_cpu(cpu)
+			pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
+					    chunk);
+		__set_bit(i, populated);
+	}
+
+	return 0;
+
+err:
+	for_each_possible_cpu(tcpu) {
+		if (tcpu == cpu)
+			break;
+		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
+				   page_end - page_start);
+	}
+	return err;
+}
+
+/**
+ * pcpu_post_map_flush - flush cache after mapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
+ * cache.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
+				int page_start, int page_end)
+{
+	unsigned int last = num_possible_cpus() - 1;
+
 	/* flush at once, please read comments in pcpu_unmap() */
 	flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
 			 pcpu_chunk_addr(chunk, last, page_end));
-	return 0;
 }
 
 /**
@@ -636,39 +856,45 @@ static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
  * CONTEXT:
  * pcpu_alloc_mutex.
  */
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
-				  bool flush)
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
 {
 	int page_start = PFN_DOWN(off);
 	int page_end = PFN_UP(off + size);
-	int unmap_start = -1;
-	int uninitialized_var(unmap_end);
-	unsigned int cpu;
-	int i;
+	struct page **pages;
+	unsigned long *populated;
+	int rs, re;
+
+	/* quick path, check whether it's empty already */
+	pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+		if (rs == page_start && re == page_end)
+			return;
+		break;
+	}
 
-	for (i = page_start; i < page_end; i++) {
-		for_each_possible_cpu(cpu) {
-			struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+	/* immutable chunks can't be depopulated */
+	WARN_ON(chunk->immutable);
 
-			if (!*pagep)
-				continue;
+	/*
+	 * If control reaches here, there must have been at least one
+	 * successful population attempt so the temp pages array must
+	 * be available now.
+	 */
+	pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
+	BUG_ON(!pages);
 
-			__free_page(*pagep);
+	/* unmap and free */
+	pcpu_pre_unmap_flush(chunk, page_start, page_end);
 
-			/*
-			 * If it's partial depopulation, it might get
-			 * populated or depopulated again.  Mark the
-			 * page gone.
-			 */
-			*pagep = NULL;
+	pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
+		pcpu_unmap_pages(chunk, pages, populated, rs, re);
 
-			unmap_start = unmap_start < 0 ? i : unmap_start;
-			unmap_end = i + 1;
-		}
-	}
+	/* no need to flush tlb, vmalloc will handle it lazily */
+
+	pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
+		pcpu_free_pages(chunk, pages, populated, rs, re);
 
-	if (unmap_start >= 0)
-		pcpu_unmap(chunk, unmap_start, unmap_end, flush);
+	/* commit new bitmap */
+	bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
 }
 
 /**
@@ -685,50 +911,61 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
  */
 static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
 {
-	const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
 	int page_start = PFN_DOWN(off);
 	int page_end = PFN_UP(off + size);
-	int map_start = -1;
-	int uninitialized_var(map_end);
+	int free_end = page_start, unmap_end = page_start;
+	struct page **pages;
+	unsigned long *populated;
 	unsigned int cpu;
-	int i;
+	int rs, re, rc;
 
-	for (i = page_start; i < page_end; i++) {
-		if (pcpu_chunk_page_occupied(chunk, i)) {
-			if (map_start >= 0) {
-				if (pcpu_map(chunk, map_start, map_end))
-					goto err;
-				map_start = -1;
-			}
-			continue;
-		}
+	/* quick path, check whether all pages are already there */
+	pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) {
+		if (rs == page_start && re == page_end)
+			goto clear;
+		break;
+	}
 
-		map_start = map_start < 0 ? i : map_start;
-		map_end = i + 1;
+	/* need to allocate and map pages, this chunk can't be immutable */
+	WARN_ON(chunk->immutable);
 
-		for_each_possible_cpu(cpu) {
-			struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+	pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
+	if (!pages)
+		return -ENOMEM;
 
-			*pagep = alloc_pages_node(cpu_to_node(cpu),
-						  alloc_mask, 0);
-			if (!*pagep)
-				goto err;
-			pcpu_set_page_chunk(*pagep, chunk);
-		}
+	/* alloc and map */
+	pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+		rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
+		if (rc)
+			goto err_free;
+		free_end = re;
 	}
 
-	if (map_start >= 0 && pcpu_map(chunk, map_start, map_end))
-		goto err;
+	pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+		rc = pcpu_map_pages(chunk, pages, populated, rs, re);
+		if (rc)
+			goto err_unmap;
+		unmap_end = re;
+	}
+	pcpu_post_map_flush(chunk, page_start, page_end);
 
+	/* commit new bitmap */
+	bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
+clear:
 	for_each_possible_cpu(cpu)
 		memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0,
 		       size);
-
 	return 0;
-err:
-	/* likely under heavy memory pressure, give memory back */
-	pcpu_depopulate_chunk(chunk, off, size, true);
-	return -ENOMEM;
+
+err_unmap:
+	pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
+	pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
+		pcpu_unmap_pages(chunk, pages, populated, rs, re);
+	pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
+err_free:
+	pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
+		pcpu_free_pages(chunk, pages, populated, rs, re);
+	return rc;
 }
 
 static void free_pcpu_chunk(struct pcpu_chunk *chunk)
@@ -752,7 +989,6 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
 	chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
 	chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
 	chunk->map[chunk->map_used++] = pcpu_unit_size;
-	chunk->page = chunk->page_ar;
 
 	chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
 	if (!chunk->vm) {
@@ -933,7 +1169,7 @@ static void pcpu_reclaim(struct work_struct *work)
 	mutex_unlock(&pcpu_alloc_mutex);
 
 	list_for_each_entry_safe(chunk, next, &todo, list) {
-		pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false);
+		pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
 		free_pcpu_chunk(chunk);
 	}
 }
@@ -981,7 +1217,6 @@ EXPORT_SYMBOL_GPL(free_percpu);
 
 /**
  * pcpu_setup_first_chunk - initialize the first percpu chunk
- * @get_page_fn: callback to fetch page pointer
  * @static_size: the size of static percpu area in bytes
  * @reserved_size: the size of reserved percpu area in bytes, 0 for none
  * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
@@ -992,14 +1227,6 @@ EXPORT_SYMBOL_GPL(free_percpu);
  * perpcu area.  This function is to be called from arch percpu area
  * setup path.
  *
- * @get_page_fn() should return pointer to percpu page given cpu
- * number and page number.  It should at least return enough pages to
- * cover the static area.  The returned pages for static area should
- * have been initialized with valid data.  It can also return pages
- * after the static area.  NULL return indicates end of pages for the
- * cpu.  Note that @get_page_fn() must return the same number of pages
- * for all cpus.
- *
  * @reserved_size, if non-zero, specifies the amount of bytes to
  * reserve after the static area in the first chunk.  This reserves
  * the first chunk such that it's available only through reserved
@@ -1031,8 +1258,7 @@ EXPORT_SYMBOL_GPL(free_percpu);
  * The determined pcpu_unit_size which can be used to initialize
  * percpu access.
  */
-size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
-				     size_t static_size, size_t reserved_size,
+size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
 				     ssize_t dyn_size, size_t unit_size,
 				     void *base_addr)
 {
@@ -1041,8 +1267,7 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
 	size_t size_sum = static_size + reserved_size +
 			  (dyn_size >= 0 ? dyn_size : 0);
 	struct pcpu_chunk *schunk, *dchunk = NULL;
-	unsigned int cpu;
-	int i, nr_pages;
+	int i;
 
 	/* santiy checks */
 	BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
@@ -1056,8 +1281,8 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
 	pcpu_unit_pages = unit_size >> PAGE_SHIFT;
 	pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
 	pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
-	pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
-		+ num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
+	pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
+		BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
 
 	if (dyn_size < 0)
 		dyn_size = pcpu_unit_size - static_size - reserved_size;
@@ -1087,8 +1312,8 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
 	schunk->vm = &first_vm;
 	schunk->map = smap;
 	schunk->map_alloc = ARRAY_SIZE(smap);
-	schunk->page = schunk->page_ar;
 	schunk->immutable = true;
+	bitmap_fill(schunk->populated, pcpu_unit_pages);
 
 	if (reserved_size) {
 		schunk->free_size = reserved_size;
@@ -1106,38 +1331,19 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
 
 	/* init dynamic chunk if necessary */
 	if (dyn_size) {
-		dchunk = alloc_bootmem(sizeof(struct pcpu_chunk));
+		dchunk = alloc_bootmem(pcpu_chunk_struct_size);
 		INIT_LIST_HEAD(&dchunk->list);
 		dchunk->vm = &first_vm;
 		dchunk->map = dmap;
 		dchunk->map_alloc = ARRAY_SIZE(dmap);
-		dchunk->page = schunk->page_ar;	/* share page map with schunk */
 		dchunk->immutable = true;
+		bitmap_fill(dchunk->populated, pcpu_unit_pages);
 
 		dchunk->contig_hint = dchunk->free_size = dyn_size;
 		dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
 		dchunk->map[dchunk->map_used++] = dchunk->free_size;
 	}
 
-	/* assign pages */
-	nr_pages = -1;
-	for_each_possible_cpu(cpu) {
-		for (i = 0; i < pcpu_unit_pages; i++) {
-			struct page *page = get_page_fn(cpu, i);
-
-			if (!page)
-				break;
-			*pcpu_chunk_pagep(schunk, cpu, i) = page;
-		}
-
-		BUG_ON(i < PFN_UP(static_size));
-
-		if (nr_pages < 0)
-			nr_pages = i;
-		else
-			BUG_ON(nr_pages != i);
-	}
-
 	/* link the first chunk in */
 	pcpu_first_chunk = dchunk ?: schunk;
 	pcpu_chunk_relocate(pcpu_first_chunk, -1);
@@ -1160,23 +1366,6 @@ static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size,
 	return size_sum;
 }
 
-/*
- * Embedding first chunk setup helper.
- */
-static void *pcpue_ptr __initdata;
-static size_t pcpue_size __initdata;
-static size_t pcpue_unit_size __initdata;
-
-static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
-{
-	size_t off = (size_t)pageno << PAGE_SHIFT;
-
-	if (off >= pcpue_size)
-		return NULL;
-
-	return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off);
-}
-
 /**
  * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
  * @static_size: the size of static percpu area in bytes
@@ -1207,18 +1396,19 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
 ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
 				      ssize_t dyn_size)
 {
-	size_t chunk_size;
+	size_t size_sum, unit_size, chunk_size;
+	void *base;
 	unsigned int cpu;
 
 	/* determine parameters and allocate */
-	pcpue_size = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
+	size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
 
-	pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
-	chunk_size = pcpue_unit_size * num_possible_cpus();
+	unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+	chunk_size = unit_size * num_possible_cpus();
 
-	pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
-					    __pa(MAX_DMA_ADDRESS));
-	if (!pcpue_ptr) {
+	base = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
+				       __pa(MAX_DMA_ADDRESS));
+	if (!base) {
 		pr_warning("PERCPU: failed to allocate %zu bytes for "
 			   "embedding\n", chunk_size);
 		return -ENOMEM;
@@ -1226,33 +1416,18 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
 
 	/* return the leftover and copy */
 	for_each_possible_cpu(cpu) {
-		void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
+		void *ptr = base + cpu * unit_size;
 
-		free_bootmem(__pa(ptr + pcpue_size),
-			     pcpue_unit_size - pcpue_size);
+		free_bootmem(__pa(ptr + size_sum), unit_size - size_sum);
 		memcpy(ptr, __per_cpu_load, static_size);
 	}
 
 	/* we're ready, commit */
 	pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
-		pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size);
+		size_sum >> PAGE_SHIFT, base, static_size);
 
-	return pcpu_setup_first_chunk(pcpue_get_page, static_size,
-				      reserved_size, dyn_size,
-				      pcpue_unit_size, pcpue_ptr);
-}
-
-/*
- * 4k page first chunk setup helper.
- */
-static struct page **pcpu4k_pages __initdata;
-static int pcpu4k_unit_pages __initdata;
-
-static struct page * __init pcpu4k_get_page(unsigned int cpu, int pageno)
-{
-	if (pageno < pcpu4k_unit_pages)
-		return pcpu4k_pages[cpu * pcpu4k_unit_pages + pageno];
-	return NULL;
+	return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+				      unit_size, base);
 }
 
 /**
@@ -1279,23 +1454,25 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
 				   pcpu_fc_populate_pte_fn_t populate_pte_fn)
 {
 	static struct vm_struct vm;
+	int unit_pages;
 	size_t pages_size;
+	struct page **pages;
 	unsigned int cpu;
 	int i, j;
 	ssize_t ret;
 
-	pcpu4k_unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size,
-					 PCPU_MIN_UNIT_SIZE));
+	unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size,
+				  PCPU_MIN_UNIT_SIZE));
 
 	/* unaligned allocations can't be freed, round up to page size */
-	pages_size = PFN_ALIGN(pcpu4k_unit_pages * num_possible_cpus() *
-			       sizeof(pcpu4k_pages[0]));
-	pcpu4k_pages = alloc_bootmem(pages_size);
+	pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
+			       sizeof(pages[0]));
+	pages = alloc_bootmem(pages_size);
 
 	/* allocate pages */
 	j = 0;
 	for_each_possible_cpu(cpu)
-		for (i = 0; i < pcpu4k_unit_pages; i++) {
+		for (i = 0; i < unit_pages; i++) {
 			void *ptr;
 
 			ptr = alloc_fn(cpu, PAGE_SIZE);
@@ -1304,25 +1481,24 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
 					   "4k page for cpu%u\n", cpu);
 				goto enomem;
 			}
-			pcpu4k_pages[j++] = virt_to_page(ptr);
+			pages[j++] = virt_to_page(ptr);
 		}
 
 	/* allocate vm area, map the pages and copy static data */
 	vm.flags = VM_ALLOC;
-	vm.size = num_possible_cpus() * pcpu4k_unit_pages << PAGE_SHIFT;
+	vm.size = num_possible_cpus() * unit_pages << PAGE_SHIFT;
 	vm_area_register_early(&vm, PAGE_SIZE);
 
 	for_each_possible_cpu(cpu) {
 		unsigned long unit_addr = (unsigned long)vm.addr +
-			(cpu * pcpu4k_unit_pages << PAGE_SHIFT);
+			(cpu * unit_pages << PAGE_SHIFT);
 
-		for (i = 0; i < pcpu4k_unit_pages; i++)
+		for (i = 0; i < unit_pages; i++)
 			populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
 
 		/* pte already populated, the following shouldn't fail */
-		ret = __pcpu_map_pages(unit_addr,
-				       &pcpu4k_pages[cpu * pcpu4k_unit_pages],
-				       pcpu4k_unit_pages);
+		ret = __pcpu_map_pages(unit_addr, &pages[cpu * unit_pages],
+				       unit_pages);
 		if (ret < 0)
 			panic("failed to map percpu area, err=%zd\n", ret);
 
@@ -1340,19 +1516,18 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
 
 	/* we're ready, commit */
 	pr_info("PERCPU: %d 4k pages per cpu, static data %zu bytes\n",
-		pcpu4k_unit_pages, static_size);
+		unit_pages, static_size);
 
-	ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
-				     reserved_size, -1,
-				     pcpu4k_unit_pages << PAGE_SHIFT, vm.addr);
+	ret = pcpu_setup_first_chunk(static_size, reserved_size, -1,
+				     unit_pages << PAGE_SHIFT, vm.addr);
 	goto out_free_ar;
 
 enomem:
 	while (--j >= 0)
-		free_fn(page_address(pcpu4k_pages[j]), PAGE_SIZE);
+		free_fn(page_address(pages[j]), PAGE_SIZE);
 	ret = -ENOMEM;
 out_free_ar:
-	free_bootmem(__pa(pcpu4k_pages), pages_size);
+	free_bootmem(__pa(pages), pages_size);
 	return ret;
 }
 
@@ -1370,16 +1545,6 @@ static size_t pcpul_unit_size;
 static struct pcpul_ent *pcpul_map;
 static struct vm_struct pcpul_vm;
 
-static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
-{
-	size_t off = (size_t)pageno << PAGE_SHIFT;
-
-	if (off >= pcpul_size)
-		return NULL;
-
-	return virt_to_page(pcpul_map[cpu].ptr + off);
-}
-
 /**
  * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
  * @static_size: the size of static percpu area in bytes
@@ -1475,9 +1640,8 @@ ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
 	pr_info("PERCPU: Remapped at %p with large pages, static data "
 		"%zu bytes\n", pcpul_vm.addr, static_size);
 
-	ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
-				     reserved_size, dyn_size, pcpul_unit_size,
-				     pcpul_vm.addr);
+	ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+				     pcpul_unit_size, pcpul_vm.addr);
 
 	/* sort pcpul_map array for pcpu_lpage_remapped() */
 	for (i = 0; i < num_possible_cpus() - 1; i++)